Catalyst for conversion of hydrocarbons, process of making and process of using thereof—Ge zeolites

ABSTRACT

This invention is for a catalyst for conversion of hydrocarbons. The catalyst is a medium pore germanium zeolite, a germanium aluminophosphate (AlPO) or a germanium silicoaluminophosphate (SAPO). At least one metal selected from Group 10 is deposited on the medium pore zeolite and, optionally on the germanium aluminophosphate (AlPO) or a germanium silicoaluminophosphate (SAPO). The catalyst is prepared by synthesizing a medium pore zeolite, an aluminophosphate (AlPO) or a silicoaluminophosphate (SAPO) with germanium incorporated into the framework and calcining the medium pore germanium zeolite, germanium aluminophosphate (AlPO) or germanium silicoaluminophosphate (SAPO). At least one metal may be deposited on the germanium zeolite, germanium aluminophosphate (AlPO) or a germanium silicoaluminophosphate (SAPO). The catalyst may be used in a process for the conversion of hydrocarbons, such as propane to aromatics, by contacting the catalyst with a hydrocarbon stream containing alkanes having 2 to 12 carbon atoms per molecule and recovering the product.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a catalyst for hydrocarbon conversion, e.g., acatalyst for the aromatization of alkanes, olefins and mixture thereofhaving two to twelve carbon atoms per molecule. The catalyst is amicroporous silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate on which a metal has been deposited.

2. Description of the Prior Art

Crystalline silicates, aluminosilicates, aluminophosphates andsilicoaluminophosphates are known catalysts for hydrocarbon conversionand may contain other metals. An aluminosilicate such as a zeolite mayinclude not only aluminum and silicon but other trivalent elements whichreplace aluminum and other tetravalent elements which replace silicon.Also, other elements may be deposited on the silicate, aluminosilicate,aluminophosphate or silicoaluminophosphate.

U.S. Pat. No. 4,310,440 discloses crystalline aluminophosphates having aframework structure with chemical composition in mole ratios of 1Al₂O₃:1.0±0.2 P₂O₅ and being microporous with uniform pores of nominaldiameters from about 3 to about 10 angstroms.

U.S. Pat. No. 4,440,871 discloses crystalline microporoussilicoaluminophosphates having pores which are uniform and have nominaldiameters of greater than about 3 angstroms with a chemical compositionof mole fractions of silicon, aluminum and phosphorus within thepentagonal composition area defined by

Mole Fraction x y z A 0.01 0.47 0.52 B 0.94 0.01 0.05 C 0.98 0.01 0.01 D0.39 0.60 0.01 E 0.01 0.60 0.39where x, y and z are the mole fractions of silicon, aluminum andphosphorus and ACBDE are points defining a pentagonal area of a ternarydiagram as shown in FIG. 1 of U.S. Pat. No. 4,440,871.

SUMMARY OF THE INVENTION

This invention provides a catalyst containing silicon, aluminum,phosphorus, as needed to form a silicate, aluminosilicate,aluminophosphate (AlPO) or silicoaluminophosphate (SAPO) with at leastone other element selected from Group 4, Group 5, Group 13, Group 14,Group 15 and the first series transition metals in a three dimensionalinterconnecting crystalline tetrahedral framework. The crystallinetetrahedral framework is synthesized from an aqueous gel containing, asneeded, a silica source, an aluminum source, a phosphorus source, asource for the Group 4, Group 5, Group 13, Group 14, Group 15 and thefirst series transition metal element(s) and, optionally, an organicstructure-directing agent. The reaction mixture is heated to formcrystals and then cooled. The crystals are separated from the synthesisliquor and are washed, dried and calcined. At least one metal selectedfrom Group 6, Group 7, Group 8, Group 9 or Group 10 is deposited on thesilicate, aluminosilicate, aluminophosphate or silicoaluminophosphate(hereinafter referred to as “deposited metal”). The catalyst may be usedin a process for converting C₂-C₁₂ hydrocarbons into aromatics.

One example of the invention is a catalyst on which at least one Group10 metal, such as platinum, is deposited on a medium pore zeolite havingat least one element selected from Group 14 other than silicon, such asgermanium, in the zeolite framework. This example includes a process forsynthesizing a medium pore zeolite catalyst by: a) preparing a mediumpore zeolite containing at least one element selected from Group 14other than silicon, such as germanium; b) depositing at least one metalselected from Group 10, such as platinum, on the medium pore zeolite;and c) calcining the medium pore zeolite on which the Group 10 metal isdeposited. This example of the invention also includes a process for theconversion of hydrocarbons of: a) contacting a hydrocarbon streamcontaining alkanes, olefins and mixtures thereof having 2 to 12 carbonatoms per molecule with at least one medium pore zeolite-based catalystwherein the zeolite contains germanium incorporated into the zeoliteframework and wherein at least one metal selected from Group 10, such asplatinum, has been deposited on the medium pore zeolite; and b)recovering the product. Examples of medium pore zeolites are ZSM-11,ZSM-12 and ZSM-48.

Another example of the invention is a catalyst of an aluminophosphate(AlPO) or silicoaluminophosphate (SAPO) with germanium incorporated intothe aluminophosphate (ALPO) or silicoaluminophosphate (SAPO) frameworkand, optionally, with at least one metal selected from Group 10deposited on the aluminophosphate (AlPO) or silicoaluminophosphate(SAPO). This example includes a process for synthesizing a zeolite bypreparing an aluminophosphate (AlPO) or silicoaluminophosphate (SAPO)with germanium incorporated into the aluminophosphate (AlPO) orsilicoaluminophosphate (SAPO) framework and calcining thealuminophosphate (AlPO) or silicoaluminophosphate (SAPO)aluminophosphate (AlPO) or silicoaluminophosphate (SAPO). Optionally, atleast one metal selected from Group 10 is deposited on thealuminophosphate (AlPO) or silicoaluminophosphate (SAPO), and saidcalcining occurs after preparation of the aluminophosphate (AlPO) orsilicoaluminophosphate (SAPO), before depositing at least one metalselected from Group 10 on the aluminophosphate (AlPO) orsilicoaluminophosphate (SAPO) or after depositing at least one metalselected from Group 10 on the aluminophosphate (AlPO) orsilicoaluminophosphate (SAPO). This example of the invention alsoincludes a process for the conversion of hydrocarbons of contacting ahydrocarbon stream containing alkanes, olefins and mixtures thereofhaving 2 to 12 carbon atoms per molecule with at least onealuminophosphate (AlPO) or silicoaluminophosphate (SAPO)-based catalystwherein the catalyst contains germanium incorporated into thealuminophosphate (AlPO) or silicoaluminophosphate (SAPO) framework and,optionally, wherein at least one metal selected from Group 10 has beendeposited on the aluminophosphate (AlPO) or silicoaluminophosphate(SAPO) depositing at least one metal selected from Group 10 on thealuminophosphate (AlPO) or silicoaluminophosphate (SAPO and recoveringthe product.

Another example of the invention is a medium pore zeolite havinggermanium incorporated into the zeolite framework. The zeolite may havea pore structure that is one dimensional, two dimensional or threedimensional. Examples of the medium pore zeolite are ZSM-11, ZSM-12 orZSM-48. This example includes a process for synthesizing a zeolite bypreparing a medium pore zeolite containing germanium in the framework ofthe zeolite and calcining the zeolite.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings:

FIGS. 1 (A and B) is an XRD of Pt/Ge-ZSM-5

FIG. 2 is a SEM of Ge-ZSM-11 (morphology 1)

FIG. 3 is an XRD of Ge-ZSM-11 (morphology 1)

FIG. 4 is a SEM of Ge-ZSM-11 (morphology 2)

FIG. 5 is an XRD of Ge-ZSM-11 (morphology 2)

FIG. 6 is a SEM of Ge-ZSM-12

FIG. 7 is an XRD of Ge-ZSM-12

FIG. 8 is a graph of propane conversion, BTX selectivity and fuel gasselectivity for Pt/[Ge; Al]ZSM-11

FIG. 9 is a graph of propane conversion, BTX selectivity and fuel gasselectivity for Pt/[Ge; Al]ZSM-48

DETAILED DESCRIPTION OF THE INVENTION

Crystalline silicates, aluminosilicates, aluminophosphates andsilicoaluminophosphates have uniform pores through which molecules candiffuse. Aluminosilicates include zeolites. Examples of zeolites are MFI(ZSM-5), BEA (Beta), MWW (MCM-22), MOR (Mordenite), LTL (Zeolite L), MTT(ZSM-23), MTW (ZSM-12), TON (ZSM-22), MEL (ZSM-11), LTA (Linde Type A),CHA (chabazite), VFI (VPI-5), MSE (MCS-68), MOZ (ZSM-10), ZSM-48, MAZ(Mazzite), MEI (ZSM-18), MFS (ZSM-57), NES (NU-87), OFF (Offretite), STI(Stilbite), BOG (Boggsite), ERI (Erionite), FAU (Faujasite), EUO (EU-1),FER (Ferrierite) and GME (Gemelinite). Examples of medium pore zeolitesare MFI, MEL, LTL, BEA, MOR, MWW, MTT, MTW, TON, MSE, MOZ, ZSM-48, MAZ,MEI, MFS, NES, OFF, STI, BOG, ERI, FAU, EUO, FER and GME with porediameters in the range from 5 angstroms to 8 angstroms. Zeolites,including medium pore zeolites, have pore structures that are onedimensional (1D), two dimensional (2D) or three dimensional (3D). MTWand ZSM-48 are examples of zeolites with a 1D pore structure. MEL is anexample of a zeolite with a 2D pore structure. MFI and BEA are examplesof zeolites with a 3D pore structure.

Crystalline silicates, aluminosilicates, aluminophosphates andsilicoaluminophosphates have structures of TO₄ tetrahedra, which form athree dimensional network by sharing oxygen atoms where T representstetravalent elements, such as silicon, trivalent elements, such asaluminum, and pentavalent elements, such as phosphorus. “Zeolite” in thepresent application includes aluminosilicates with openthree-dimensional framework structures (without regard to thedimensional pore structure discussed above) composed of corner-sharingTO₄ tetrahedra, where T is Al or Si, but also includes tetravalent,trivalent and divalent T atoms which are able to isoelectronicallyreplace Si and Al in the framework, e.g., germanium (4+), titanium (4+),boron (3+), gallium (3+), iron (3+), zinc (2+) and beryllium (2+).“Zeolite” is primarily a description of structure, not composition.

Silicates, aluminosilicates, aluminophosphates andsilicoaluminophosphates generally crystallize from an aqueous solution.The typical technique for synthesizing silicates, aluminosilicates,aluminophosphates or silicoaluminophosphates comprises converting anaqueous gel of a silica source, an aluminum source and a phosphorussource, as needed, to crystals by a hydrothermal process, employing adissolution/recrystallization mechanism. The reaction medium may alsocontain an organic structure-directing agent which is incorporated inthe microporous space of the crystalline network during crystallization,thus controlling the construction of the network and assisting tostabilize the structure through the interactions with the silicon,aluminum or phosphorus components. The solids content of the gel rangesfrom about 5% to about 25%. In one embodiment of the invention thesolids content ranges from about 10% to about 20%.

The aqueous gel contains, in addition to the silica source, the aluminumsource, the phosphorus source, as needed, and the optional organicstructure-directing agent, a source of at least one other element fromGroup 4, Group 5, Group 13, Group 14, Group 15 or the first seriestransition metals to be incorporated into the framework of the silicate,aluminosilicate, aluminophosphate or silicoaluminophosphate.

Examples of the silica source are silicon oxide or silica (SiO₂) whichis available in various forms, such as silica sol, commerciallyavailable as Ludox AS-40™, precipitated silica, commercially availableas Ultrasil VN3SP™ and fumed silica, commercially available as Aerosil200™.

Examples of the aluminum source are sodium aluminate, aluminum nitrate,aluminum sulfate, aluminum hydroxide and pseudobohemite.

Examples of the phosphorus source are orthophosphoric acid,triethylphosphate and sodium metaphosphate.

Examples of the source of Group 4, Group 5, Group 13, Group 14, Group 15and the first series transition metals are oxides, chlorides, sulfates,alkoxides, fluorides, nitrates and oxalates.

Examples of the structure-directing agent are organic amine andquaternary ammonium compounds and salts and cations thereof, such astetra n-propyl ammonium hydroxide, tetra n-propyl ammonium bromide andtetra n-propyl ammonium chloride, tetraethyl ammonium hydroxide,hexamethyleneimine, 1,4-di(1′4′-diazabicyclo[2.2.2]octane)butanehydroxide, morpholine, cyclohexylamine and diethylethanolamine,N,N′-diisopropyl imidazolium cation, tetrabutylammonium compounds,di-n-propylamine (DPA), tripropylamine, triethylamine (TEA),triethanolamine, piperidine, 2-methylpyridine, N,N-dimethylbenzylamine,N,N-diethylethanolamine, dicyclohexylamine, N,N-dimethylethanolamine,choline cation, N,N′-dimethylpiperazine, 1,4-diazabicyclo(2,2,2)octane,N′,N′,N,N-tetramethyl-(1,6)hexanediamine, N-methyldiethanolamine,N-methyl-ethanolamine, N-methyl piperidine, 3-methyl-piperidine,N-methylcyclohexylamine, 3-methylpyridine, 4-methyl-pyridine,quinuclidine, N,N′-dimethyl-1,4-diazabicyclo(2,2,2)octane ion;di-n-butylamine, neopentylamine, di-n-pentylamine, isopropylamine,t-butyl-amine, ethylenediamine, pyrrolidine, 2-imidazolidone, aN-benzyl-1,4-diazabicyclo[2.2.2]octane cation, a1-[1-(4-chlorophenyl)-cyclopropylmethyl]-1-ethyl-pyrrolidinium or1-ethyl-1-(1-phenyl-cyclopropylmethyl)-pyrrolidium cation and mixturethereof. Specific examples of structure directing agents are tetraethylammonium bromide; 1,8-diaminooctane; 1,6-hexanediamine;tetramethylammonium chloride; tetraethylammonium bromide;tetrabutylammonium bromide. Other specific examples of structuredirecting agents are tetrapropylammonium hydroxide (or bromide) forGe-ZSM-5; tetrabutyloammonium bromide for ZSM-11 and Ge-ZSM-11;tetraethylammonium hydroxide for ZSM-12, Ge-ZSM-12, Al-Beta andGe—Al-Beta and 1,6-Hexanediamine for ZSM-48 and Ge-ZSM-48.

The reaction may also utilize an acid as a reagent. The acid may be aBronsted acid or a Lewis acid. Examples without limitation of an aciduseful in the present invention are sulfuric acid, acetic acid, nitricacid, phosphoric acid, hydrochloric acid, hydrofluoric acid, oxalic acidor formic acid. One example of the pH of the reaction mixture forzeolites is from about 9 to about 13. Another example of the pH of thereaction mixture for zeolites is from about 9.5 to about 12.5. Otherexamples of the pH of the reaction mixture are about 9.2 for Ge-ZSM-5;11.2 to 12.6 for Ge-ZSM-11; 12.4 for Ge-ZSM-12 and 13.8 for Ge—Al-Beta.One example of the pH of the reaction mixture for aluminophosphate(AlPO) or silicoaluminophosphate (SAPO) is about 3 to about 9. Anotherexample of the pH of the reaction mixture for aluminophosphate (AlPO) orsilicoaluminophosphate (SAPO) is about 4 to about 8.

The reaction mixture may sit statically or may be stirred about 600 rpmfor one to seven days and heated to a temperature of about 100° C. toabout 200° C. to form crystals. In one embodiment of the invention thetemperature range was from about 135° C. to about 180° C. The reactionmixture is cooled to room temperature in a range form 15 to 60 minutesat a rate of from about 3° C. to 10° C. per minute. The crystals areseparated from the synthesis liquor.

The liquid portion of the synthesis liquor may be removed by filtration,evaporation, spray drying or any other means for removing water from thecrystals. The crystals are washed with water and then dried andcalcined.

The silicates are essentially aluminum-free but may contain aluminum andother impurities up to 500 ppm.

The aluminosilicates may have a silicon to aluminum atomic ratio (Si:Al)greater than 2:1. In one embodiment of the present invention, thesilicon to aluminum atomic ratio is in the range from 15:1 to 200:1. Inanother embodiment of the present invention, the silicon to aluminumatomic ratio is in the range from 18:1 to 100:1.

The aluminophosphates may have an aluminum to phosphorus atomic ratio(Al:P) in the range from about 0.8:1 to about 1.2:1 as disclosed in U.S.Pat. No. 4,310,440, hereby incorporated by reference.

The silicoaluminophosphates may have a silicon to aluminum to phosphorusatomic ratio represented by (S_(x)Al_(y)P_(z))O₂ where “x”, “y” and “z”represent the mole fractions of silicon, aluminum and phosphorusrespectively, present as tetrahedral oxides, said mole fractions beingsuch that they are within the pentagonal compositional area defined bypoints ABCD and E of a ternary diagram with values represented in thetable below:

Mole Fraction x y z A 0.01 0.47 0.52 B 0.94 0.01 0.05 C 0.98 0.01 0.01 D0.39 0.60 0.01 E 0.01 0.60 0.39as disclosed in U.S. Pat. No. 4,440,871, hereby incorporated byreference.

The amount of Group 4, Group 5, Group 13, Group 14, Group 15 and thefirst series transition metals present in the crystalline framework isin the range from 0.1 wt. % to 25 wt. %. In one embodiment of thepresent invention, this range is from 0.1 wt. % to 10 wt. %. In anotherembodiment of the present invention, this range is from 0.1 wt. % to 5wt. %.

The silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate has average pore size in the range from 2angstroms to 20 angstroms, i.e., microporous.

At least one metal selected from Group 6, Group 7, Group 8, Group 9 orGroup 10 is deposited on the silicate, aluminosilicate, aluminophosphateor silicoaluminophosphate (“deposited metal”). The metal is depositednot only on the surface of the silicate, aluminosilicate,aluminophosphate or silicoaluminophosphate but also in the pores andchannels which occur in the silicate, aluminosilicate, aluminophosphateor silicoaluminophosphate. The metal is deposited on the silicate,aluminosilicate, aluminophosphate or silicoaluminophosphate by any knownmethod of depositing a metal on a silicate, aluminosilicate,aluminophosphate or silicoaluminophosphate. Typical methods ofdepositing a metal on a silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate are ion exchange and impregnation. In oneembodiment of the present invention, the metal is present in the rangefrom 0.05% to 3% by weight. In another embodiment of the presentinvention, the metal is present in the range from 0.1% to 2% by weight.In another embodiment of the present invention, the metal is present inthe range from 0.2 to 1.5% by weight.

However, for silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate-based catalysts on which metals have beendeposited, the process temperatures and catalyst regenerationtemperatures cause the metal to “sinter”, i.e., agglomeration of themetal particles resulting in an increase of metal particle size on thesurface of the zeolite and a decrease of metal surface area, causing aloss of catalyst performance, specifically catalyst performance, e.g.,activity and/or selectivity.

Without the present invention and its claims being limited by theory, itis believed that certain elements in the framework and certain metalsdeposited on the silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate associate to resist sintering of the depositedmetal. U.S. Pat. No. 6,784,333 discloses and claims analuminum-silicon-germanium zeolite on which platinum has been depositedfor use in a process for the aromatization of hydrocarbons. The presenceof germanium in the framework of the zeolite and the presence ofplatinum deposited on the zeolite apparently results in higherselectivity for benzene, toluene and xylenes (BTX) which remainsessentially constant over a significant time on stream. Without theinvention of U.S. Pat. No. 6,784,333 and its claims being limited bytheory, it may be that the germanium in the framework and the platinumdeposited on the zeolite associate such that the platinum remainsdispersed and sintering is reduced. The association of certain elementsin the framework and certain deposited metals may be present forzeolites other than ZSM-5 as disclosed in U.S. Pat. No. 6,784,333. Otherzeolites may be synthesized with germanium in the framework and platinumdeposited on the zeolite to form Pt/Ge-zeolite catalysts.

Besides germanium, there may be other elements in the crystallineframework which associate with platinum or other deposited metals.Elements in the crystalline framework may be selected from Group 4,Group 5, Group 13, Group 14, Group 15 and the first series transitionmetals of the Periodic Table of Elements. Specific examples of theseelements are germanium, boron, gallium, indium, tin, titanium,zirconium, vanadium, chromium, iron, niobium and phosphorus. One or moreelements may be in the crystalline framework.

Besides platinum, there may be other deposited metals which associatewith germanium or other elements in the crystalline framework. Depositedmetals may be selected from Group 6, Group 7, Group 8, Group 9 and Group10 of the Periodic Table of Elements. Specific examples of the depositedmetal are platinum, molybdenum, rhenium, nickel, ruthenium, rhodium,palladium, osmium and iridium. One or more metals, such as bimetallics,e.g., Pt/Sn, Pt/Ge, Pt/Pb or metal/metal oxide combinations, e.g.Pt/GeO₂, may be deposited.

The crystalline framework of which these elements from Group 4, Group 5,Group 13, Group 14, Group 15 and the first series transition metals arepart and on which metals selected from Group 6, Group 7, Group 8, Group9 and Group 10 are deposited need not be limited to a zeolite but may beany microporous silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate.

Before or after deposition of the metal, the silicate, aluminosilicate,aluminophosphate or silicoaluminophosphate may be bound by oxides orphosphates of magnesium, aluminum, titanium, zirconium, thorium,silicon, boron or mixtures thereof. The process steps of binding anddepositing metal can occur in any order. Binding may occur before orafter metal deposition.

The catalyst may be calcined at different stages in the synthesis. Thesilicate, aluminosilicate, aluminophosphate or silicoaluminophosphatemay be calcined to remove the organic structure-directing agent. Thiscalcination is at a temperature of about 300° C. to about 1000° C. orabout 300° C. to about 750° C. for a time sufficient to removeessentially all of any structure-directing agent, e.g., one to six hoursor about four hours. One example of calcination is at 550° C. for tenhours. Calcination may occur after binding. This calcination is at atemperature in the range of from about 300° C. to about 1000° C. for atime in the range of from about one hour to about 24 hours. Calcinationmay also occur after metal deposition to fix the metal. This calcinationshould not exceed a temperature of 500° C. and may be at a temperatureof about 200° C. to about 500° C. for a time in the range of from about0.5 hour to about 24 hours. These calcinations need not be separate butmay be combined to accomplish more than one purpose. When the silicate,aluminosilicate, aluminophosphate or silicoaluminophosphate is calcined,it may be bound or unbound and it may have metal deposited on it or not.

The catalyst, bound or unbound, will have porosity in addition to theuniform porosity of the silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate. For an unbound catalyst, the average pore sizeof the catalyst can vary for bound and unbound catalyst and is in therange from 2 angstroms to 100 angstroms. In one embodiment of thepresent invention, the average pore size is in the range from 5angstroms to 50 angstroms. In another embodiment of the presentinvention, the average pore size is in the microporous range from 5angstroms to 20 angstroms. For a bound catalyst, the average pore sizeof the catalyst may vary from 5 angstroms up to 100 microns.

Some catalysts used for hydrocarbon conversion are susceptible to sulfurpoisoning. However, for some catalysts used for hydrocarbon conversion,modest amounts of sulfur, such as about 0 to 200 ppm in the feed, areacceptable and sometimes preferred. The catalyst may also be pretreatedwith sulfur. A standard sulfurization method that is well known in theart consists in heating in the presence of a sulfur compound, such ashydrogen sulfide, or a mixture of a sulfur compound and an inert gas,such as hydrogen or nitrogen, to a temperature of between 150 and 800°C. Non-limiting examples of sulfur compounds are H₂S, an organosulfidecompound, such as dimethyl disulfide or DMSO (dimethyl sulfoxide), orC_(n)H_(2n+2)S or C_(n)H_(2n+2)S₂, where n=1−20. In one embodiment ofthe present invention, the temperature is between 250 and 600° C.

The catalyst may contain a reaction product, such as a sulfide of thedeposited metal, that is formed by contacting the catalyst with sulfuror a sulfur compound. In one embodiment of the present invention, theamount of sulfur on the catalyst is in the range of from 10 ppm to 0.1wt. %.

The catalyst may also contain elements other than sulfur, such as tin,germanium or lead. These elements would be present in the range of from1:1 to 1:100 as a ratio of the deposited metal to tin, germanium orlead. These elements may be added to the catalyst by wet impregnation,chemical vapor deposition or other methods known in the art.

The silicate, aluminosilicate, aluminophosphate orsilicoaluminophosphate-based catalyst which contains at least oneelement selected from Group 4, Group 5, Group 13, Group 14, Group 15 andthe first series transition metals isomorphously incorporated into thezeolite framework and at least one metal selected from Group 6, Group 7,Group 8, Group 9 and Group 10 deposited on the zeolite can be used in aprocess for conversion of hydrocarbon streams containing C₂-C₁₂ alkanes,olefins or mixtures thereof, which may be straight, branched, cyclic ormixtures thereof, into aromatics.

The zeolite may be base-exchanged with an alkali metal or alkaline earthmetal, such as cesium, potassium, sodium, rubidium, barium, calcium,magnesium and mixtures thereof, to reduce acidity and form a non-acidiczeolite. A non-acidic zeolite has substantially all of its cationicsites of exchange, e.g., those typically associated with aluminum,occupied by nonhydrogen cationic species, e.g., alkali or alkaline earthmetals. These cationic sites are often responsible for cracking ofhydrocarbons into undesired products. A zeolite may be non-acidic byexchange with a base or, for meaning and purposes of the presentinvention, by having a low aluminum content, i.e., having aluminumcontent of no more than 0.4 wt %. The base-exchange may occur before orafter the noble metal is deposited. Such a base-exchanged catalyst maybe used to convert C₆-C₁₂ alkanes, such as might be obtained fromnatural gas condensate, light naphtha, raffinate from aromaticsextraction and other refinery or chemical processes, to aromatics, suchas benzene, ethyl benzene, toluene and xylenes. Base-exchange may takeplace during synthesis of the zeolite with an alkali metal or alkalineearth metal being added as a component of the reaction mixture or maytake place with a crystalline zeolite before or after deposition of thenoble metal. The zeolite is base-exchanged to the extent that most orall of the cations associated with aluminum are alkali metal or alkalineearth metal. An example of a monovalent base:aluminum molar ratio in thezeolite after base exchange is at least about 0.9. For a divalent ortrivalent base, the molar ratio would be half (0.45) or a third (0.3) asthat for a monovalent base, respectively, and for mixtures ofmonovalent, divalent and trivalent bases, the above molar ratios wouldbe apportioned by their respective content in the mixture.

Examples of hydrocarbon conversion processes for which this catalyst canbe used are:

(A) The catalytic cracking of a naphtha feed to produce light olefins.Typical reaction conditions include from about 500° C. to about 750° C.,pressures of subatmospheric or atmospheric, generally ranging up toabout 10 atmospheres (gauge) and catalyst residence time (volume of thecatalyst/feed rate) from about 10 milliseconds to about 10 seconds.(B) The catalytic cracking of high molecular weight hydrocarbons tolower weight hydrocarbons. Typical reaction conditions for catalyticcracking include temperatures of from about 400° C. to about 700° C.,pressures of from about 0.1 atmosphere (bar) to about 30 atmospheres,and weight hourly space velocities of from about 0.1 to about 100 hr⁻¹.(C) The transalkylation of aromatic hydrocarbons in the presence ofpolyalkylaromatic hydrocarbons. Typical reaction conditions include atemperature of from about 200° C. to about 500° C., a pressure of fromabout atmospheric to about 200 atmospheres, a weight hourly spacevelocity of from about 1 to about 100 hr⁻¹ and an aromatichydrocarbon/polyalkylaromatic hydrocarbon mole ratio of from about 1/1to about 16/1.(D) The isomerization of aromatic (e.g., xylene) feedstock components.Typical reaction conditions for such include a temperature of from about230° C. to about 510° C., a pressure of from about 0.5 atmospheres toabout 50 atmospheres, a weight hourly space velocity of from about 0.1to about 200 hr⁻¹ and a hydrogen/hydrocarbon mole ratio of from about 0to about 100.(E) The dewaxing of hydrocarbons by selectively removing straight chainparaffins. The reaction conditions are dependent in large measure on thefeed used and upon the desired pour point. Typical reaction conditionsinclude a temperature between about 200° C. and 450° C., a pressure upto 3,000 psig and a liquid hourly space velocity from 0.1 to 20 hr⁻¹.(F) The alkylation of aromatic hydrocarbons, e.g., benzene andalkylbenzenes, in the presence of an alkylating agent, e.g., olefins,formaldehyde, alkyl halides and alcohols having 1 to about 20 carbonatoms. Typical reaction conditions include a temperature of from about100° C. to about 500° C., a pressure of from about atmospheric to about200 atmospheres, a weight hourly space velocity of from about 1 hr⁻¹ toabout 100 hr⁻¹ and an aromatic hydrocarbon/alkylating agent mole ratioof from about 1/11 to about 20/1.(G) The alkylation of aromatic hydrocarbons, e.g., benzene, with longchain olefins, e.g., C₁₄ olefin. Typical reaction conditions include atemperature of from about 50° C. to about 200° C., a pressure of fromabout atmospheric to about 200 atmospheres, a weight hourly spacevelocity of from about 2 hr⁻¹ to about 2000 hr⁻¹ and an aromatichydrocarbon/olefin mole ratio of from about 1/1 to about 20/1. Theresulting products from the reaction are long chain alkyl aromaticswhich when subsequently sulfonated have particular application assynthetic detergents.(H) The alkylation of aromatic hydrocarbons with light olefins toprovide short chain alkyl aromatic compounds, e.g., the alkylation ofbenzene with propylene to provide cumene. Typical reaction conditionsinclude a temperature of from about 10° C. to about 200° C., a pressureof from about 1 to about 30 atmospheres, and an aromatic hydrocarbonweight hourly space velocity (WHSV) of from 1 hr⁻¹ to about 50 hr⁻¹.(I) The hydrocracking of heavy petroleum feedstocks, cyclic stocks, andother hydrocrack charge stocks. The zeolite-bound high silica zeolitewill contain an effective amount of at least one hydrogenation componentof the type employed in hydrocracking catalysts.(J) The alkylation of a reformate containing substantial quantities ofbenzene and toluene with fuel gas containing short chain olefins (e.g.,ethylene and propylene) to produce mono- and dialkylates. Preferredreaction conditions include temperatures from about 100° C. to about250° C., a pressure of from about 100 to about 800 psig, a WHSV-olefinfrom about 0.4 hr⁻¹ to about 0.8 hr⁻¹, a WHSV-reformate of from about 1hr⁻¹ to about 2 hr⁻¹ and, optionally, a gas recycle from about 1.5 to2.5 vol/vol fuel gas feed.(K) The alkylation of aromatic hydrocarbons, e.g., benzene, toluene,xylene, and naphthalene, with long chain olefins, e.g., C₁₄ olefin, toproduce alkylated aromatic lube base stocks. Typical reaction conditionsinclude temperatures from about 100° C. to about 400° C. and pressuresfrom about 50 to 450 psig.(L) The alkylation of phenols with olefins or equivalent alcohols toprovide long chain alkyl phenols. Typical reaction conditions includetemperatures from about 100° C. to about 250° C., pressures from about 1to 300 psig and total WHSV of from about 2 hr⁻¹ to about 10 hr⁻¹.(M) The conversion of light paraffins to olefins and/or aromatics.Typical reaction conditions include temperatures from about 425° C. toabout 760° C. and pressures from about 10 to about 2000 psig.(N) The conversion of light olefins to gasoline, distillate and luberange hydrocarbons. Typical reaction conditions include temperatures offrom about 175° C. to about 500° C. and a pressure of from about 10 toabout 2000 psig.(O) Two-stage hydrocracking for upgrading hydrocarbon streams havinginitial boiling points above about 200° C. to premium distillate andgasoline boiling range products or as feed to further fuels or chemicalsprocessing steps. The first stage can be the zeolite-bound high silicazeolite comprising one or more catalytically active substances, e.g., aGroup 8 metal, and the effluent from the first stage would be reacted ina second stage using a second zeolite, e.g., zeolite Beta, comprisingone or more catalytically active substances, e.g., a Group 8 metal, asthe catalyst. Typical reaction conditions include temperatures fromabout 315° C. to about 455° C., a pressure from about 400 to about 2500psig, hydrogen circulation of from about 1000 to about 10,000 SCF/bbland a liquid hourly space velocity (LHSV) of from about 0.1 to 10 hr⁻¹.(P) A combination hydrocracking/dewaxing process in the presence of thezeolite-bound high silica zeolite comprising a hydrogenation componentand a zeolite such as zeolite Beta. Typical reaction conditions includetemperatures from about 350° C. to about 400° C., pressures from about1400 to about 1500 psig, LHSV from about 0.4 to about 0.6 hr⁻¹ and ahydrogen circulation from about 3000 to about 5000 SCF/bbl.(Q) The reaction of alcohols with olefins to provide mixed ethers, e.g.,the reaction of methanol with isobutene and/or isopentene to providemethyl-t-butyl ether (MTBE) and/or t-amyl methyl ether (TAME). Typicalconversion conditions include temperatures from about 20° C. to about200° C., pressures from 2 to about 200 atm, WHSV (gram-olefin perhour-gram-zeolite) from about 0.1 hr⁻¹ to about 200 hr⁻¹ and an alcoholto olefin molar feed ratio from about 0.1/1 to about 5/1.(R) The disproportionation of aromatics, e.g. the disproportionation oftoluene to make benzene and xylenes. Typical reaction conditions includea temperature of from about 200° C. to about 760° C., a pressure of fromabout atmospheric to about 60 atmosphere (bar), and a WHSV of from about0.1 hr⁻¹ to about 30 hr⁻¹.(S) The conversion of naphtha (e.g., C₆-C₁₀) and similar mixtures tohighly aromatic mixtures. Thus, normal and slightly branched chainedhydrocarbons, preferably having a boiling range above about 40° C., andless than about 200° C., can be converted to products having asubstantially higher octane aromatics content by contacting thehydrocarbon feed with the zeolite at a temperature in the range of fromabout 400° C. to 6000° C., preferably 480° C. to 550° C. at pressuresranging from atmospheric to 40 bar, and liquid hourly space velocities(LHSV) ranging from 0.1 to 15 hr⁻¹.(T) The adsorption of alkyl aromatic compounds for the purpose ofseparating various isomers of the compounds.(U) The conversion of oxygenates, e.g., alcohols, such as methanol, orethers, such as dimethylether, or mixtures thereof to hydrocarbonsincluding olefins and aromatics with reaction conditions including atemperature of from about 275° C. to about 600° C., a pressure of fromabout 0.5 atmosphere to about 50 atmospheres and a liquid hourly spacevelocity of from about 0.1 to about 100.(V) The oligomerization of straight and branched chain olefins havingfrom about 2 to about 5 carbon atoms. The oligomers which are theproducts of the process are medium to heavy olefins which are useful forboth fuels, i.e., gasoline or a gasoline blending stock, and chemicals.The oligomerization process is generally carried out by contacting theolefin feedstock in a gaseous state with a zeolite-bound high silicazeolite at a temperature in the range of from about 250° C. to about800° C., a LHSV of from about 0.2 to about 50 and a hydrocarbon partialpressure of from about 0.1 to about 50 atmospheres. Temperatures belowabout 250° C. may be used to oligomerize the feedstock when thefeedstock is in the liquid phase when contacting the zeolite-bound highsilica zeolite catalyst. Thus, when the olefin feedstock contacts thecatalyst in the liquid phase, temperatures of from about 10° C. to about250° C. can be used.(W) The conversion of C₂ unsaturated hydrocarbons (ethylene and/oracetylene) to aliphatic C₆₋₁₂ aldehydes and converting said aldehydes tothe corresponding C₆₋₁₂ alcohols, acids, or esters.(X) The desulfurization of FCC (fluid catalytic cracking) feed streams.The desulfurization process is generally carried out at a temperatureranging from 100° C. to about 600° C., preferably from about 200° C. toabout 500° C., and more preferably from about 260° C. to about 400° C.,at a pressure ranging from 0 to about 2000 psig, preferably from about60 to about 1000 psig, and more preferably from about 60 to about 500psig, at a LHSV ranging from 1 to 10 h⁻¹. The hydrocarbon mixtures whichcan be desulfurized according to the process of the present inventioncontain more than 150 ppm of sulfur, e.g., hydrocarbon mixtures with asulfur content higher than 1000 ppm, even higher than 10000 ppm.

The invention having been generally described, the following examplesare given as particular embodiments of the invention and to demonstratethe practice and advantages thereof. It is understood that the examplesare given by way of illustration and are not intended to limit thespecification or the claims to follow in any manner.

EXAMPLE 1 Synthesis of Ge-ZSM-5

Chemicals Used:

Ludox AS-40 colloidal silica SiO2; 40 wt. % suspension in water;Aldrich;

Sodium hydroxide NaOH, 50 wt. % solution in water; Sigma-Aldrich;Germanium dioxide GeO₂; Germanium Corporation of America GTAH 68002;

Sodium aluminate NaAlO₂ (23.6 wt. % Al₂O₃; 19.4 wt. % Na₂O; 57.0 wt. %H₂O); Southern Ionics;

Tetrapropylammonium hydroxide (CH₃CH₂CH₂)₄NOH, 40 wt. % solution inwater; SACHEM;

Acetic acid CH₃CO₂H, 99.7%; Aldrich.

Solution 1.

15.84 grams of sodium hydroxide solution were mixed with 131.25 grams ofD.I. water. 7.11 grams of GeO₂ were dissolved in the solution withstirring.

Solution 2.

3.84 grams of sodium aluminate were mixed with 153.9 grams of D.I.water.

Solution 1 was poured into 150 grams of Ludox AS-40 with vigorous gelstirring for 10 minutes. Then Solution 2 was introduced and gel wasstirred for 15 minutes. Tetrapropylammonium hydroxide (105.42 grams) wasadded to the mixture and gel was stirred for about one hour. 23.32 gramsof acetic acid was added to the gel with continuous stirring. pH of gelafter ten minutes of stirring was 9.25. Crystallization was made in 1 Lstainless steel autoclave at 160° C. with stirring (300 rpm) for 36hours. Zeolite was filtered and washed with D.I. water. Zeolite wasdried at 90° C. overnight and was calcined at 550° C. for 10 hours inoven forced with air.

XRF analysis results are: 0.244 wt. % Na; 41.04 wt. % Si; 0.73 wt. % Al;5.67% Ge.

XRD analysis confirmed formation of ZSM-5 structure.

Pt/CsGeZSM-5

15 grams of laboratory prepared GeZSM-5 was washed with 350 ml ofaqueous CsNO3 (0.5M) then filtered. The filtrate was then rewashed 3more times with 0.5M CsNO3 and rinsed with distilled H2O on the finalfiltering. The zeolite powder was then calcined for 3 hours at 280° C.in air.

Incipient wetness impregnation was carried out by adding drop wise asolution of 0.0408 g Pt(NH2)4(NO3)2 dissolved in 0.8150 g of deionizedwater to 1.99 grams of the Cs-exchanged GeZSM-5. The material was driedfor 1 hour in a 110° C. drying oven then calcined in air at 280° C. for3 hours.

Elemental analysis gave 41.0 wt % Si, 0.71 wt % Al, 5.27 wt % Cs, 4.13wt % Ge and 0.96 wt % Pt.

XRD analysis confirmed formation of ZSM-5 structure (FIGS. 1, A and B)

The catalyst powder was pressed and sized to 20-40 mesh. 0.25 cm³ (0.123g) of the sized catalyst was mixed with 1.75 ml of inert quartz chipsand was pretreated at 460° C. for 1 hour in flowing H2. Catalytictesting was then started.

Catalyst particles, mixed with inert quartz chips, were loaded into a ¼″OD plug flow reactor. n-hexane was vaporized into a stream of flowinghydrogen at a temperature of approximately 150° C. This gas mixture waspassed through the reactor at a LHSV of 8.6 hr⁻¹, the reactor beingmaintained at a temperature of 515° C. by an external heating jacket.The reaction products were analyzed by gas chromatography. Productsranging in size from methane to dimethylnaphthalene were observed. Avariety of C6 isomerization products were observed, including isohexanes(e.g., 2-methylpentane) and olefins (e.g. 1-hexene.) For the purposes ofcalculating conversion and selectivity, these C6 products wereconsidered to be unreacted. The selectivities reported are calculated asthe sum of benzene, toluene, xylenes, and ethylbenzene produced dividedby the total amount of all benzene, C1-C5, and C7+ materials recovered.These selectivities are presented on a molar C6 basis.

catalyst X₁₀ S₁₀ Pt/CsGeZSM-5 24 88

Performance of ZSM-5 Catalysts for N-Hexane Aromatization

T=515° C., LHSV=8.6 hr⁻¹, H₂/n-hexane feed ratio=0.75. Conversion andaromatics selectivity measured after 10 hours on stream.

EXAMPLE 2 Synthesis of Ge-ZSM-11 (Morphology 1)

Chemicals Used:

Sodium aluminate (Al₂O₃-23.6%; Na₂O-19.4%; H₂O-57%); Southern Ionics;

Sodium hydroxide, >98%, Aldrich;

Tetrabutylammonium bromide, 98%; Sigma-Aldrich;

Ludox HS-30; colloidal silica, 30% suspension in water; Sigma-Aldrich;

Germanium (IV) oxide GeO2, Germanium Corporation of America GTAH 68002.

1.7 grams of sodium aluminate and 2.817 grams of sodium hydroxide weredissolved in 136.0 grams of D.I. water. 28.16 grams oftetrabutylammonium bromide were added and dissolved in the solution.2.8452 grams of germanium oxide were dissolved in the solution.Colloidal silica Ludox HS-30 (80 grams) was introduced into solutionwith stirring for about 15 minutes. pH of gel was 12.61. Crystallizationwas made in 300 ml stainless steel autoclave at 150° C. for 144 hourswith stirring (200 rpm) Material was filtered and washed with D.I water.Material was dried overnight at 90° C., sieved 40 mesh size and calcinedat 550° C. for 10 hours in a furnace with forced air flow.

XRF analysis data for sample: 42.50 wt. % Si; 0.99 wt. % Al; 1.177 wt. %Na; 2.81 wt. % Ge.

A SEM of Ge-ZSM-11 (morphology 1) is shown in FIG. 2.

XRD analysis confirmed formation of ZSM-11 structure by comparison withpublished pattern for ZSM-11 in references such as “Collection ofSimulated XRD Powder Patterns for Zeolites”, 5^(th) edition, M. M. J.Treacy & J. B. Higgins, Amsterdam: Elsevier (2007). See FIG. 3.

Synthesis of 1% Pt/CsGeZSM-11

4 grams of laboratory prepared GeZSM-11 (morphology 1) was washed with200 ml of aqueous CsNO3 (0.5M) then filtered. The filtrate was thenrewashed 3 more times with 0.5M CsNO3 and rinsed with distilled H₂O onthe final filtering. The zeolite powder was then calcined for 3 hours at280° C. in air.

Incipient wetness impregnation was carried out by adding drop wise asolution of 0.0396 g Pt(NH2)4(NO3)2 dissolved in 1.962 g of deionizedwater to 1.962 grams of the Cs-exchanged ZSM-11. The material was driedfor 1 hour in a 110° C. drying oven then calcined in air at 280° C. for3 hours. Elemental analysis is shown below.

The catalyst powder was pressed and sized to 20-40 mesh. 0.25 cm3 (0.124g) of the sized catalyst was mixed with 1.75 ml of inert quartz chipsand was pretreated at 460° C. for 1 hour in flowing H2. Catalytictesting was then started.

EXAMPLE 3 Synthesis of Ge-ZSM-11 (Morphology 2)

Chemicals Used:

Aluminum sulfate hydrate Al₂(SO₄)₃.xH₂O, 99.998%; Aldrich;

Potassium hydroxide, >90%; Sigma-Aldrich;

1,8-Diaminooctane, 98%; Aldrich;

Ludox HS-30; colloidal silica, 30% suspension in water; Sigma-Aldrich;

Germanium (IV) oxide, Germanium Corporation of America GTAH 68002;

Sulfuric acid, 95-98%; Sigma-Aldrich.

7.2 grams of aluminum sulfate hydrate was dissolved in 544 grams of D.I.water. Potassium hydroxide (16 grams) was dissolved in the solution.6.83 grams of germanium oxide were dissolved in the same solution. 64grams of 1,8-diaminooctane were added into solution and dissolved withstirring. Colloidal silica Ludox HS-30 (192 grams) was introducedgradually into solution with stirring. White gel was formed. Gel wasstirred for about 1 hour. Then 10 ml of sulfuric acid were addedgradually with vigorous solution stirring. pH of gel was about 11.

Crystallization was made in 1 L stainless steel autoclave at 160° C. for120 hours with stirring (200 rpm). Material was filtered and washed withD.I water. Material was dried overnight at 90° C., sieved to 40 meshsize and calcined at 550° C. for 10 hours in the furnace with forced airflow.XRF analysis data for sample: 40.80 wt. % Si; 1.12 wt. % Al; 1.06 wt. %K; 5.52 wt. % Ge.A SEM of Ge-ZSM-11 (morphology 2) is shown in FIG. 4.XRD analysis confirmed formation of ZSM-11 structure by comparison withpublished pattern for ZSM-11 in references such as “Collection ofSimulated XRD Powder Patterns for Zeolites”, 5^(th) edition, M. M. J.Treacy & J. B. Higgins, Amsterdam: Elsevier (2007). See FIG. 5.

Synthesis of 1% Pt/CsGeZSM-11

3 grams of laboratory prepared GeZSM-11 (morphology 2) was washed with150 ml of aqueous CsNO3 (0.5M) then filtered. The filtrate was thenrewashed 3 more times with 0.5M CsNO3 and rinsed with distilled H2O onthe final filtering. The zeolite powder was then calcined for 3 hours at280° C. in air.

Incipient wetness impregnation was carried out by adding drop wise asolution of 0.0398 g Pt(NH2)4(NO3)2 dissolved in 1.00 g of deionizedwater to 2.002 grams of the Cs-exchanged ZSM-11. The material was driedfor 1 hour in a 110° C. drying oven then calcined in air at 280° C. for3 hours. Elemental analysis is shown below.

The catalyst powder was pressed and sized to 20-40 mesh. 0.25 cm3 (0.129g) of the sized catalyst was mixed with 1.75 ml of inert quartz chipsand was pretreated at 460° C. for 1 hour in flowing H2. Catalytictesting was then started.

Elemental Analyses for Pt/CsGeZSM-11 Catalysts as Tested

catalyst Si Al Ge Cs Na Pt Pt/CsGeZSM- 41.63% 0.96% 0.90% 8.68% 0.07%0.98% 11 morphology 1 Pt/CsGeZSM- 42.14% 1.06% 0.82% 8.74%  0.0% 0.97%11 morphology 2

Catalyst particles, mixed with inert quartz chips, were loaded into a ¼″OD plug flow reactor. n-hexane was vaporized into a stream of flowinghydrogen at a temperature of approximately 150° C. This gas mixture waspassed through the reactor at a LHSV of 8.6 hr⁻¹, the reactor beingmaintained at a temperature of 515° C. by an external heating jacket.The reaction products were analyzed by gas chromatography. Productsranging in size from methane to dimethylnaphthalene were observed. Avariety of C6 isomerization products were observed, including isohexanes(e.g., 2-methylpentane) and olefins (e.g. 1-hexene.) For the purposes ofcalculating conversion and selectivity, these C6 products wereconsidered to be unreacted. The selectivities reported are calculated asthe sum of benzene, toluene, xylenes, and ethylbenzene produced dividedby the total amount of all benzene, C₁-C₅, and C7+ materials recovered.These selectivities are presented on a molar C6 basis.

catalyst comments added X₁₀ S₁₀ Pt/CsGeZSM-11 morphology 1 0.90% Ge 1189 Pt/CsGeZSM-11 morphology 2 0.82% Ge 16 89

Performance of ZSM-11 Catalysts for N-Hexane Aromatization

T=515° C., LHSV=8.6 hr⁻¹, H₂/n-hexane feed ratio=0.75. Conversion andaromatics selectivity measured after 10 hours on stream.

EXAMPLE 4 Synthesis of Ge-ZSM-12

Chemicals Used:

Sodium hydroxide NaOH, 50% solution in water, Aldrich;

Sodium aluminate NaAlO₂ (23.6 wt. % Al₂O₃; 19.4 wt. % Na₂O; 57.0 wt. %H₂O); Southern Ionics;

Germanium dioxide GeO₂; Germanium Corporation of America GTAH 68002;

Tetraethylammonium hydroxide (CH₂CH₂)₄NOH; 35% w/w aq. soln.;Alfa-Aesar;

Ludox HS-30 SiO₂ colloidal silica (30 wt. %); Sigma-Aldrich.

2.0042 grams of sodium hydroxide, 1.6808 grams of sodium aluminate and26.29 grams of tetraethylammonium hydroxide were mixed in 25.00 grams ofD.I. water. 3.0648 grams of germanium dioxide were dissolved in thissolution.

100 grams of silica source Ludox HS-30 were added to solution graduallywith stirring. Stirring continued for one hour. Viscous gel was formed.

Crystallization was done at 160° C. for about 6 days in Teflon lined 300ml reactor in static regime. After crystallization pH=12.01. Materialwas filtered and washed with D.I. water. Material was dried at 90° C.,sieved 40 mesh size, and calcined at 600° C. for 10 hours.

A SEM of Ge-ZSM-12 is shown in FIG. 6.

XRF analysis results are: 0.793 wt. % Na; 43.97 wt. % Si; 0.69 wt. % Al;3.28 wt. % Ge.

XRD analysis confirmed formation of ZSM-12 structure (FIG. 7).

Pt/CsGeZSM-12

3.22 grams of laboratory prepared GeZSM-12 (361-032) was washed with 150ml of aqueous CsNO3 (0.5M) then filtered. The filtrate was then rewashed3 more times with 0.5M CsNO3 and rinsed with distilled H2O on the finalfiltering. The zeolite powder was then calcined for 3 hours at 280° C.in air.

Incipient wetness impregnation was carried out by adding drop wise asolution of 0.0410 g Pt(NH2)4(NO3)2 dissolved in 1.04 g of deionizedwater to 2.012 grams of the Cs-exchanged GeZSM-12. The material wasdried for 1 hour in a 110° C. drying oven then calcined in air at 280°C. for 3 hours. Elemental analysis gave 42.95 wt % Si, 5.83 wt % Cs,0.70 wt % Al, 1.60 wt % Ge, and 0.80 wt % Pt.

The catalyst powder was pressed and sized to 20-40 mesh. 0.25 cm3 (0.127g) of the sized catalyst was mixed with 1.75 ml of inert quartz chipsand was pretreated at 460° C. for 1 hour in flowing H2. Catalytictesting was then started.

Catalyst particles, mixed with inert quartz chips, were loaded into a ¼″OD plug flow reactor. n-hexane was vaporized into a stream of flowinghydrogen at a temperature of approximately 150° C. This gas mixture waspassed through the reactor at a LHSV of 8.6 hr⁻¹, the reactor beingmaintained at a temperature of 515° C. by an external heating jacket.The reaction products were analyzed by gas chromatography. Productsranging in size from methane to dimethylnaphthalene were observed. Avariety of C6 isomerization products were observed, including isohexanes(e.g., 2-methylpentane) and olefins (e.g. 1-hexene.) For the purposes ofcalculating conversion and selectivity, these C6 products wereconsidered to be unreacted. The selectivities reported are calculated asthe sum of benzene, toluene, xylenes, and ethylbenzene produced dividedby the total amount of all benzene, C1-C5, and C7+ materials recovered.These selectivities are presented on a molar C6 basis.

Catalyst X₁₀ S₁₀ Pt/CsGeZSM-12 16 87

Performance of ZSM-5 Catalysts for N-Hexane Aromatization

T=515° C., LHSV=8.6 hr⁻¹, H₂/n-hexane feed ratio=0.75. Conversion andaromatics selectivity measured after 10 hours on stream.

EXAMPLE 5 Pt/Ge-ZSM-11

Chemicals Used:

Aluminum sulfate hydrate Al₂(SO₄)₃.xH₂O, 99.998%; Aldrich;

Potassium hydroxide KOH; >90%; Sigma-Aldrich;

1,8-Diaminooctane NH₂(CH₂)₈NH₂, 98%; Aldrich;

Ludox HS-30 colloidal silica, 30% suspension in water; Sigma-Aldrich;

Germanium (IV) oxide GeO₂, Germanium Corporation of America GTAH 68002;

Sulfuric acid H₂SO₄; 95-98%; Sigma-Aldrich.

7.2 grams of aluminum sulfate hydrate was dissolved in 544 grams of D.I.water. Potassium hydroxide (16 grams) was dissolved in the solution.6.83 grams of germanium oxide were dissolved in the same solution. 64grams of 1,8-diaminooctane were added into solution and dissolved withstirring. Colloidal silica Ludox HS-30 (192 grams) was introducedgradually into solution with stirring. Gel was formed and stirred forabout 1 hour. Then 10 ml of sulfuric acid were added gradually withvigorous solution stirring. pH of gel was about 11.

Crystallization was made in 1 L stainless steel autoclave at 160° C. for120 hours with stirring (200 rpm). Material was filtered and washed withD.I water. Material was dried overnight at 90° C., sieved to 40 meshsize and calcined at 550° C. for 10 hours in the furnace with forced airflow.

XRF analysis data for sample: 0.518 wt. % Na; 40.80 wt. % Si; 1.12 wt. %Al; 1.06 wt. % K; 5.52 wt. % Ge.

Ge-ZSM-11 zeolite was bound with silica at 50/50 wt. Bound zeolite wasdried at 90° C. and calcined at 550° C. for 6 hours. Material wascrushed and sieved to 20/40 mesh size. Then ion-exchange with ammoniumwas made by sample treatment with 0.5M NH₄NO₃ at 60° C. in three steps.Sample was rinsed with D.I. water, dried at 90° C. and calcined at 550°C. for 6 hours.

Platinum was introduced into catalyst by ion-exchange with 0.005M(NH₂)₄Pt(NO₃)₂ at 60° C. After rinsing with D.I. water catalyst wasdried at 60° C. overnight and calcined in air at 300° C. for 5.5 hours.

XRF analysis results are: 0.045 wt. % Na; 45.77 wt. % Si; 0.53 wt. % Al;0.89 wt. % Ge; 0.36 wt. % Pt; K was not detected.

EXAMPLE 6 Pt/Ge-ZSM-48

Chemicals Used:

Sodium hydroxide NaOH, 50% solution in water; Sigma-Aldrich;

Hi-Sil®233 Sio2, hydrated amorphous silica; PPG Industries, Inc.;

1,6-Diaminohexane H₂N(CH₂)₆NH₂; 98+%, Alfa-Aesar;

Ethanol CH₃CH₂OH; 94-96%; Alfa-Aesar;

Germanium (IV) oxide GeO₂, Germanium Corporation of America GTAH 68002.

4.5597 grams of sodium hydroxide solution was added to 40 grams of D.I.water. Germanium oxide (2.2846 g) was introduced and dissolved. 363.86grams of D.I. water was added to solution. 38.5 grams of silica sourceHi-Sil®233 was introduced with stirring. Mixture was stirred for about10 minutes. Then 1,6-diaminohexane (28 grams) was added to mixture andstirring was continuous overnight. 9.1 grams of ethanol was added withstirring. pH of mixture was 11.74.

Crystallization was done at 160° C. for 4 days in 1 L stainless steelautoclave with stirring (300 rpm.).

Material was filtered and washed with D.I water. Material was driedovernight at 90° C., sieved to 40 mesh size and calcined at 600° C. for10 hours in the furnace with forced air flow.

XRF analysis data for sample: 0.428 wt. % Na; 45.38 wt. % Si; 0.30 wt. %Al; 1.01 wt. % Ge.

Ge-ZSM-48 zeolite was bound with silica at 50/50 wt. Bound zeolite wasdried at 90° C. and calcined at 550° C. for 6 hours. Material wascrushed and sieved to 20/40 mesh size. Then ion-exchange with ammoniumwas made by sample treatment with 0.5M NH₄NO₃ at 60° C. in three steps.Sample was rinsed with D.I. water, dried at 90° C. and calcined at 550°C. for 6 hours.

Platinum was introduced into catalyst by ion-exchange with 0.005M(NH₂)₄Pt(NO₃)₂ at 60° C. After rinsing with D.I. water catalyst wasdried at 60° C. overnight and calcined in air at 300° C. for 5.5 hours.

XRF analysis results are: 0.055 wt. % Na; 46.43 wt. % Si; 0.17 wt. % Al;0.19 wt. % Ge; 0.12 wt. % Pt.

All catalysts were tested in a stainless steel tube at 500° C. using 34cc/min propane at 22 psig total pressure. The products were analyzed byon-line sampling to a gas chromatograph where all hydrocarbon componentswith carbon numbers between 1 and 10 were quantitatively determined.Results for yield [fraction of BTX (benzene, toluene, xylenes) inproduct] and conversion (portion of propane converted) are shown in thegraphs below.

Numerous modifications and variations of the present invention arepossible in light of the above teachings. It is to be understood that,within the scope of the appended claims, the invention may be practicedother than as specifically described.

What is claimed as new and desired to be secured by Letter of Patent ofthe United States of America is:
 1. A catalyst for conversion ofhydrocarbons comprising: a) a medium pore zeolite having germaniumincorporated into the zeolite framework, wherein the zeolite isnon-acidic; and a metal selected from Group 10 deposited on the mediumpore zeolite; and wherein the zeolite is MEL, BEA, MWW, MTW, ZSM-48, orFER.
 2. The catalyst of claim 1 wherein the metal deposited on themedium pore zeolite is platinum.
 3. A process for synthesizing a mediumpore zeolite catalyst comprising: a) preparing a medium pore zeolitecontaining germanium in the framework of the zeolite, wherein thezeolite is non-acidic and is MEL, BEA, MWW, MTW, ZSM-48, or FER; b)depositing a metal selected from Group 10 on the medium pore zeolite;and c) calcining the medium pore zeolite during preparation of thezeolite or before or after depositing the Group 10 metal.
 4. The processof claim 3 wherein the metal deposited on the medium pore is platinum.5. The process of claim 3 wherein the zeolite is base-exchanged with analkali metal or alkaline earth metal to make the zeolite non-acidic. 6.The process of claim 5 wherein the zeolite is base-exchanged withcesium, potassium, sodium, rubidium, barium, calcium, magnesium ormixtures thereof.
 7. A zeolite comprising: a medium pore zeolite havinggermanium incorporated into the zeolite framework, wherein the zeoliteis non-acidic and is MEL, BEA, MWW, MTW, ZSM-48, or FER.
 8. A processfor synthesizing a zeolite comprising: a) preparing a medium porezeolite containing germanium in the framework of the zeolite, whereinthe zeolite is non-acidic and is MEL, BEA, MWW, MTW, ZSM-48, or FER; b)calcining the zeolite.
 9. The catalyst of claim 1, wherein the zeoliteis MEL.
 10. A process for synthesizing a zeolite comprising: a)preparing a medium pore zeolite containing germanium in the framework ofthe zeolite, wherein the zeolite is MEL, BEA, MWW, MTW, ZSM-48, or FER;b) base exchanging the zeolite with an alkali metal or alkaline earthmetal to make the zeolite non-acidic; and c) calcining the zeolite.